In contrast to ALCs that have been in use for many years, DWLs
have undergone recent development using solid-state fiber-optic technology at a wavelength of -1.5 ,um.
Maximum likelihood (ML) and diagonally weighted least squares (DWLS
) estimation procedures: a comparison of estimation bias with ordinal and multivariate non-normal data.
To make geometric phase holograms, the DWLS
uses an ultraviolet laser to 'print' on a super-thin film--only about 50 nanometers thick.
model comparison test (i.e., [DELTA]S-B[chi square] [[DELTA]df, p]) adjusted for non-normality under DWLS
The maximum likelihood (ML) method was selected as the estimation method, because it converges more rapidly and the results are also easier to interpret compared with the "distribution free" approach (e.g., DWLS
Mais especificamente, tres modelos poderiam ser usados: DWLS
(Diagonizaded Weighted Least Square ou Minimos Quadrados Ponderados Diagonalizados), WLS (Weighted Least Square ou Minimos Quadrados Ponderados) e PLS-PM.
We did this using the distance weighted least squares (DWLS
) smoothing method that fits the lines through a set of points by least squares.
Los metodos de estimacion empleados en el AFC fueron ML, GLS, y minimos cuadrados con ponderacion diagonal (DWLS
Asymptotic Distribution Free estimates (WLS and DWLS
methods in LISREL and the AGLS method in EQS) appear to be inappropriate for small samples (i.e., fewer than 400 cases) (Aiken & West, 1991; Hu, Bentler & Kano, 1992; Jaccard & Wan, 1995).
A map of the canonical surface was produced using the interpolation algorithm DWLS
(distance weighted least squares) from SYSTAT/SYGRAPH (Wilkinson 1989).
This procedure, however, requires a sample size larger than those that were available for these studies. A compromise suggested by Joreskog & Sorbom (1989) is to examine only the asymptotic variances of the correlation matrix, using the diagonally weighted least squares (DWLS
) method of estimation.